"I'm sure it's a question a lot of people are asking and I can assure everyone it's not something that we approached lightly," Brennan tells TVGuide.com. "It's something that I certainly wouldn't have done if I didn't think we could make it different and turn a different light on the NCIS world."

The key difference is that the characters at the heart of the new series, which will be introduced Tuesday in the first hour of a two-part NCIS: Los Angeles (9/8c, CBS), are part of the Red Team, a mobile NCIS unit that can be deployed anywhere in the country. When a murder in Idaho is connected to one in Los Angeles, Sam (LL Cool J) and Callen (Chris O'Donnell) join forces with the Red Team, led by Agent Paris Summerskill (Kim Raver).

Although all of the shows in the NCIS franchise feature a tightknit team of agents, Brennan suggests the premise of the new series automatically makes the storytelling more personal. Can you imagine NCIS' Tony and Ziva camping out in Kansas every week?

"They're forced to live and work together," Brennan says of the Red Team. "They obviously will be involved in investigations that will have the mystery and the whodunit aspect. But it really will be about the personal side to these people living together. We will certainly see more of what takes place between the characters than we do on either of the other shows, purely because they spend 24/7 together. You can't help but dip into the more emotional side."But close quarters can also be problematic. In fact, Paris has a checkered past with her last partner, Roy Haines (John Corbett). So, when Hetty (Linda Hunt) calls Roy out of retirement, the reunion isn't quite so happy. "Something happened the last time they worked together," Brennan teases. "As a result of that, Roy stopped being an agent and Paris started working alone. So, the reintroduction of this pair comes with a certain amount of conflict and tension."Then again, romance could bloom during the Red Team's current deployment. (And no, we're not talking about Sam and Callen's extremely small bunks.) "There certainly is a moment or two between Paris and Callen that is quite electric on the screen," Brennan says. "Chris O'Donnell and Kim Raver absolutely sent the sparks flying."

But it's not all about the Red Team. Fans of Kensi (Daniela Ruah) and Deeks (Eric Christian Olsen) can expect some personal developments back in Los Angeles. Four words: The box is back. "Kensi instigates something that has a long-term impact on Deeks," Brennan says. "It is major. She does something in this episode that totally and utterly surprises Deeks. It's a very revealing moment ultimately."

Although CBS most likely won't make a decision about ordering the new series until May, Brennan says that he could easily see an all-NCIS night on the 2013 fall schedule. And, given the relationship between Callen and Paris, he hopes to find intriguing ways to blend stories across the franchise.

"It's quite exciting to me to explore a relationship between two characters over two different series and if we're lucky enough to get picked up, it's something that I'll certainly be pursuing," he says. "It may not be in the classic crossover episode sense that people are used to. It may be a different approach and I have some ideas. ... It's got a lot of potential, I believe."

NCIS: Los Angeles airs Tuesdays at 9/8c on CBS. The conclusion to "Red," airs on March 26.